One of the most common questions I get from native English speakers about grammar rules concerns the difference between 'who' and 'whom' and its derivatives. Let's see if we can clear up some misconceptions about their usage.

The sentences:

Like I said, these are common mistakes, so I easily found two examples to share. Here's one I found on Twitter, which is a pretty good place to find grammar mistakes.

The biggest steal of the #NBADraft will be to whomever snags Jordan Bell in the 2nd Round.

The writer has a Master's Degree in journalism and two BAs, though in what I forget. In other words, even educated people do this.

Here's another:

"Truly, whom amongst us can forget Trump ordering the killing of bin Laden? Or Obama bragging about barging in on naked beauty contestants?"

This sentence is also from Twitter, and it is courtesy of JK Rowling. Even professional writers do this. Even. The. British.

What's bad about it?

In short, this mistake comes in the misuse of the Subject and Object.

Let's look into this. First, we need to know what subjects and objects are; and second, that what they are governs their usage.

Essentially, a subject is the thing (therefore a noun) doing an action (a verb), and the object is the thing (another noun) that is being acted upon. (Keep in mind this definition is for this illustration only.)

So if we look at this simple example sentence:

Sally kicks a ball.

We see Sally is doing the kicking and the ball is receiving that same kicking. Sally is the subject and the ball is the object.

In English, we know this is true from their placement either before or after the verb; in an active sentence, subjects come before verbs and objects after verbs. This holds true for pronouns, which obey as types of nouns. See:

She kicked it.

Simple sentence. It has a pronoun subject, an action verb, and a pronoun object. We recognize this is correct, but moreover we recognize how incorrect the following is:

*Her kicked it.

Her is an object, and therefore awkward and confusing to the native ear when it comes before the verb. (In linguistics, the * before a sentence means basically incorrect.

The difference above is easy to recognize in commonly used pronouns. But whom is uncommonly used and therefore it is not understood that who is a subject word and whom is an object word like he and him and like she and her.

Let's take the two initial example sentences and strip everything away so we're left with only the subject/verb combination, which lays bare their relationship:

whomever snags

and

whom can

Now, let's replace these less common pronouns for more common pronouns. Remember this is a great test linguists often use to discern word forms: Replace less salient words with more salient words if they follow the same rule(s).

him snags

and

her can

Have you ever heard those combinations in native usage? Highly doubtful. You'll see them written, but that's because it takes processing time for these mistakes to manifest.

Why that's bad:

Hypercorrection in this situation is only bad in that it makes obvious the fact that people are attempting -- but failing at -- creating more sophisticated grammatical constructions.

Moreover, the word whom will probably be gone in a hundred years or so. That's my guess, so I could say that the above are not mistakes such much as people being ahead of their time!

A fix:

The fix is quite simple. Remove the m and remember a very simple rule:

When the who/whom word immediately precedes the verb, no m. Boom.

So that's settled. But what's going on here?

Ok. So here's the deal. English has a case system that is not particularly salient and therefore appears inconsistent. And for now note that case is the relationship between the noun and its verb, the head of the sentence.

Most nouns don't have differ in subject and object form. But we should consider those that do:

Kangaroos kick kangaroos.

and

He kicked him.

While it takes a bit of thought to see differing relationships between each kangaroo and their verb, kick, the differing relationship is crystal clear in the sentence with pronouns. This illustrates English case. It really only exists in pronouns, so it's important to keep those pronouns clear.

Or is it?

You went with you? (Imagine someone pointing to two different people.)

English has already decided that form distinctions in case aren't entirely necessary in all pronouns. Today in 2017 how many people would argue that the following is truly incorrect?:

This fascinating language change is happening before our eyes, and in fact we are each contributing to it every time we use who where your grammar teacher told you you must use whom.

Keep in mind that errors in language may be less ignorant and more avant-garde. If clarity is maintained, the language will change. And fighting a language change rooted in the democratization of English is like trying to hold back the Mississippi River with a stern look. Good luck.